Eye position and memory saccade related responses in substantia nigra pars reticulata

Bayer, H; Handel, Ari; Glimcher, Paul W.

doi:10.1007/s00221-003-1735-7

Cited by 16 publications

(15 citation statements)

References 43 publications

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“…Neurophysiological evidence for the latter assumption exists (Basso and Wurtz 2002), but the existence of a topological projection has only been confirmed in the cat (Jiang et al 2003). Other studies dispute the Gaussian-shaped spatial tuning of the pause in SNr saccade-related activity Glimcher 1999, 2000;Bayer et al 2004). Although the resolution and form of the spatial tuning of SNr neurons are still subject to debate, we will model our responses in the present model on those reported by Basso and Wurtz (2002).…”

Section: Introductionmentioning

confidence: 65%

A model of the saccade-generating system that accounts for trajectory variations produced by competing visual stimuli

Arai

Keller

2004

Biol Cybern

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Variable saccade trajectories are produced in visual search paradigms in which multiple potential target stimuli are present. These variable trajectories provide a rich source of information that may lead to a deeper understanding of the basic control mechanisms of the saccadic system. We have used published behavioral observations and neural recordings in the superior colliculus (SC), gathered in monkeys performing visual search paradigms, to guide the construction of a new distributed model of the saccadic system. The new model can account for many of the variations in saccade trajectory produced by the appearance of multiple visual stimuli in a search paradigm. The model uses distributed feedback about current eye motion from the brainstem to the SC to reduce activity there at physiologically realistic rates during saccades. The long-range lateral inhibitory connections between SC cells used in previous models have been eliminated to match recent physiological evidence. The model features interactions between visually activated multiple populations of cells in the SC and distributed and topologically organized inhibitory input to the SC from the SNr to produce some of the types of variable saccadic trajectories, including slightly curved and averaging saccades, observed in visual search tasks. The distributed perisaccadic disinhibition of SC from the substantia nigra (SNr) is assumed to have broad spatial tuning. In order to produce the strongly curved saccades occasionally recorded in visual search, the existence of a parallel input to the saccadic burst generators in addition to that provided by the distributed input from the SC is required. The spatiotemporal form of this additional parallel input is computed based on the assumption that the input from the model SC is realistic. In accordance with other recent models, it is assumed that the parallel input comes from the cerebellum, but our model predicts that the parallel input is delayed during highly curved saccadic trajectories.

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Section: Introductionmentioning

confidence: 65%

A model of the saccade-generating system that accounts for trajectory variations produced by competing visual stimuli

Arai

Keller

2004

Biol Cybern

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“…Notably, although the connections within the cortico-striato-thalamic "loops" are well defined chemically (excitatory or inhibitory), none of them have individually been assigned a specific role in motor response inhibition. For instance, despite the focus of earlier unit recording studies on saccade-related tonic-pause neurons, more recent work have documented saccade-related "burst" neuronal responses, in the pars reticulata of the substantia nigra, an output nucleus of the basal ganglia (Bayer et al, 2004;Handel and Glimcher, 1999;Handel and Glimcher, 2000;Hikosaka and Wurtz, 1983a;Hikosaka and Wurtz, 1983b;Sato and Hikosata, 2002).…”

Section: Role Of Subthalamic Nucleus During Visual Motor Processingmentioning

confidence: 99%

Subcortical processes of motor response inhibition during a stop signal task

et al. 2008

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This PDF receipt will only be used as the basis for generating PubMed Central (PMC) documents. PMC documents will be made available for review after conversion (approx. 2-3 weeks time). Any corrections that need to be made will be done at that time. No materials will be released to PMC without the approval of an author. Only the PMC documents will appear on PubMed Central --this PDF Receipt will not appear on PubMed Central.Previous studies have delineated the neural processes of motor response inhibition during a stop signal task, with most reports focusing on the cortical mechanisms. A recent study highlighted the importance of sub-cortical processes during stop signal inhibition in 13 individuals and suggested that the subthalamic nucleus (STN) may play a role in blocking response execution (Aron and Poldrack, 2006). Here in a functional magnetic resonance imaging (fMRI) study we replicated the finding of greater activation in the STN during stop (success or error) trials, compared to go trials, in a larger sample of subjects (n=30). However, since a contrast between stop and go trials involved processes that could be distinguished from response inhibition, the role of subthalamic activity during stop signal inhibition remained to be specified. To this end we followed an alternative strategy to isolate the neural correlates of response inhibition (Li et al., 2006a). We compared individuals with short and long stop signal reaction time (SSRT) as computed by the horse race model. The two groups of subjects did not differ in any other aspects of stop signal performance. We showed greater activity in the short than the long SSRT group in the caudate head during stop successes, as compared to stop errors. Caudate activity was positively correlated with medial prefrontal activity previously shown to mediate stop signal inhibition. Conversely, bilateral thalamic nuclei and other parts of the basal ganglia, including the STN, showed greater activation in subjects with long than short SSRT. Thus, fMRI delineated contrasting roles of the prefrontal-caudate and striato-thalamic activities in mediating motor response inhibition.

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“…Several lines of evidence suggested that the SNr plays critical roles in the control of saccadic eye movements (Handel and Glimcher, 1999;Basso and Wurtz, 2002;Bayer et al, 2004;Basso et al, 2005;Basso and Liu, 2007). One of the interesting observations reported by Basso and Liu (2007) is that electrical stimulation of the SNr both reduced and prolonged saccade latency.…”

Section: Functional Implicationsmentioning

confidence: 98%

Nigral Inhibition of GABAergic Neurons in Mouse Superior Colliculus

Kaneda

Isa²,

Yanagawa³

et al. 2008

J. Neurosci.

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The current dominant concept for the control of saccadic eye movements by the basal ganglia is that release from tonic GABAergic inhibition by the substantia nigra pars reticulata (SNr) triggers burst firings of intermediate gray layer (SGI) neurons in the superior colliculus (SC) to allow saccade initiation. This hypothesis is based on the assumption that SNr cells inhibit excitatory projection neurons in the SGI. Here we show that nigrotectal fibers are connected to local GABAergic neurons in the SGI with a similar frequency to non-GABAergic neurons. This was accomplished by applying neuroanatomical tracing and slice electrophysiological experiments in GAD67-green fluorescent protein (GFP) knock-in mice, in which GABAergic neurons specifically express GFP. We also found that GABA A , but not GABA B , receptors subserve nigrotectal transmission. The present results revealed a novel aspect on the role of the basal ganglia in the control of saccades, e.g., the SNr not only regulates burst initiation but also modulates the spatiotemporal properties of premotor neurons via connections to local GABAergic neurons in the SC.

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Eye position and memory saccade related responses in substantia nigra pars reticulata

Cited by 16 publications

References 43 publications

A model of the saccade-generating system that accounts for trajectory variations produced by competing visual stimuli

A model of the saccade-generating system that accounts for trajectory variations produced by competing visual stimuli

Subcortical processes of motor response inhibition during a stop signal task

Nigral Inhibition of GABAergic Neurons in Mouse Superior Colliculus

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